DNV GL addressed at EAGC one of the issues blocking the widespread adoption of greater LNG use as a fuel by developing a new online PKI Methane Number Calculator to match fuel quality with an engine’s requirements, and also can support the development of an international standard.
Engine knock is characterized by auto-ignition of the unburned fuel mixture, known as the end gas, ahead of the propagating flame in the engine cylinder. DNV GL has developed a verified algorithm to quantify the effect of LNG quality on engine knock, and thus to help LNG users ensure safe and efficient engine operations.
“As LNG is produced at different locations around the world, using an assortment of productiontechnologies, its composition can vary considerably,” DNV GL’s Senior Vice President, Oil & Gas, Liv Hovem, said. “Determining its fitness-for-purpose can be difficult and the consequences of mismatching fuel quality to a specific ship engine can cause potentially dangerous effects such as significant loss of performance, engine shutdown and even damage. Knowledge of the knock characteristics of LNG fuels is therefore crucial for suppliers and traders to provide reliable and efficient products and to break down the perceived barriers of adopting LNG.”
The knock resistance of LNG is characterized by a methane number, similar to the octane number used in gasoline engines. Users of the tool simply enter LNG composition information such as nitrogen, methane, ethane, propane, and n-butane, and the tool calculates a PKI methane number, which can be matched with the engine specification.